60 CANDLES AND LAMPS. 



CHAPTER VH. 



CANDLES AND LAMPS. 



THEKE is a very near and intimate relation between heat 

 and light. Both come together from the sun, and both are 

 subject, in many respects, to the same laws. In other re- 

 spects, the modes of action which they present are striking- 

 ly different. The prevailing opinion among scientific men 

 at the present day is, that the phenomena of heat and of 

 light are produced by the same agent, modified in its ac- 

 tion in some mysterious way, the secret of which has not 

 yet been discovered. 



We shall see, in another chapter, the curious relation 

 which heat and light bear to each other, as they come to 

 us together in the radiance of the sun. 



One of the most striking differences between heat and 

 light is, that heat can be absorbed by any substance and 

 afterward given out again slowly, but light, apparently, is 

 not subject to this mode of action, except in a few special 

 cases, and in these only to a very limited extent. If you 

 put a brick or any other substance in the rays of a hot 

 sun, or before a bright fire, it will absorb the heat, and 

 then, if afterward you take it to a cool place and hold 

 your hand before it, you will feel the heat which it has 

 absorbed radiating from it and warming your hand ; but 

 if you take it into a dark place, your eye will not detect 

 any luminous radiance from it that is, there will be no 

 evidence to the senses that it absorbed light as well as 

 heat, so as afterward to emit it. But perhaps we can not 

 certainly infer, from the fact that our senses do not detect 



